This invention pertains to valves that can be used in the priming circuit of a pump.
It is familiar for pumps to have a valve which, when open, permits an internal circulation between the output and the intake. The water is projected into the intake inlet of the first wheel and brings with it a part of the air from the intake chamber. A depression is created in the intake and the water rises in the pipes. The water loaded with air arrives in the output chamber where the settling occurs. The settled water returns to the intake, passing through the valve, and the cycle begins again. The water rises gradually in the intake pipes as the air is eliminated. When the air is completely evacuated, the water completely fills the pump and the rise in pressure causes the valve to close. The pump is thus primed.
A pump of this sort with an automatic priming circuit, includes the valve having a pull-back spring. This spring is a mechanical piece whose spacial dimensions can be thoroughly mastered. But the pull-back spring is in the passage of the liquid, which necessitates frequent cleanings. Another pump with an automatic priming system has a valve with a bendable rubber tube. This direct-passage valve not necessitate cleaning; but the rubber tube ages over time, such that its mechanical characteristics become uncertain.
German document DE-C-222 761 discloses a pump with priming circuit containing a valve with a seating (6) that has an orifice and an obturator mounted so as to be able to be applied onto the seating in front of the orifice, the obturator is an elastic blade embedded on one side. The valve is fixed directly onto the interior of the body of the pump and acts on a second opposite element. This arrangement is not economical for a pump addressed by the invention.